The haunting files that detectives just can’t get out of their heads. Cases that have grown cold – unsolved and unfinished.

“I’ve lost a lot of sleep over these,” McHenry County Undersheriff Andrew Zinke said. “Every police officer does – especially detectives. These cases go home with you at night.”

The McHenry County Sheriff’s Office has eight open and unsolved homicide cases in its office, Zinke said. Detectives take fresh eyes to the files as time permits.

But as the weeks, months and sometimes years accumulate and leads grow more stale, with no new evidence or witnesses, it makes it harder and more frustrating for detectives to solve these crimes.

“The faster you can get [to a crime scene], the faster you can get fresh evidence, fresh witness statements,” Zinke said. “Those are all critical in making that case.”

In these cases, the critical first hours of investigation lapsed long ago.

Technological advances in evidence gathering has changed, too, making the older crimes even harder to solve.

“Go back 20 years, and basically it was fingerprints and fibers,” Zinke said of clue-collection techniques of the past. “It’s at such a higher level now. ... Looking at stuff from 1960s and 1970s, some of these homicide reports were one page.”

This story used old newspaper stories to look at two high-profile, unsolved cases that shocked the area.

An artist and a civic leader

Pamela Carr was selling her Woodstock condominium in September 1996 when her real estate agent found her bludgeoned and lying in a pool of blood.

There was no indication of forced entry into Carr’s 1089 Greenwood Place condo, and no evidence of assault other than the fatal wounds from a blunt object.

Police searched for clues and questioned suspects as Carr’s friends and family asked who would want the 53-year-old mother, artist and civic leader dead. She was on the Public Action to Deliver Shelter board.

Suspicion immediately fell on Carr’s estranged husband, Michael.

He had filed for divorce in March of the year Pamela Carr was killed, and soon after the filing, she obtained an order of protection against him.

A search of Michael Carr’s home did not lead to an arrest, and he was never charged with any wrongdoing.

Questions about who fed Pamela Carr’s dog in the three days before she was found and a missing garage door opener haunted family members and stymied detectives, who waited in vain for a witness or anyone with information to come forward. No one materialized.

The murder weapon never was found, and with little physical evidence, Woodstock police have yet to find Pamela Carr’s killer.

The on-duty officer

It was a murder case that stole headlines for months. It had everything to captivate readers – drama, betrayal, a sexual liaison.

On-duty Hampshire police Sgt. Greg Sears was shot execution style on a stormy night on June 1, 2000, off Route 20 at Elgiloy Drive in Kane County. It was the sergeant’s first day back to work after a major stroke a month before.

Investigators instantly homed in on Sears’ lifelong friend John Carroccia, based on statements from Sears’ new bride, Norma Jean. Carroccia and Greg Sears grew up together in Marengo.

Norma Jean Sears told investigators on the night of Greg’s murder that the men had a falling-out over her marriage to the veteran officer.

Norma Jean and Greg Sears were married a few weeks before his murder.

Carroccia was arrested on the steps of Norma Jean’s home as he was visiting his best friend’s widow.

But as Carroccia’s trial went on, Norma Jean Sears claimed that a medical condition wiped out all memory of the month her husband was killed. In the wake of her mental breakdown, she no longer could remember statements she made to police.

Still, for investigators, all signs pointed to Carroccia. It looked like an open-and-shut case.

Witnesses saw what police alleged was Carroccia’s van leaving the crime scene. During his trial, though, those same witnesses could not read signs 50 feet away.

The 12-day trial brought to light an affair Greg Sears had with a married woman before his marriage to Norma Jean and other jaw-dropping details.

After a little more than two hours of deliberation, a Kane County jury declared Carroccia not guilty.

Police and prosecutors said at the time that they wouldn’t reopen the case unless new evidence materialized.

“We’re confident we charged the right guy,” the Kane County assistant state’s attorney said at the time.

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Sooner or later, these crimes disappear from headlines and fade into memory for most.

But not those of detectives or the victims’ families, who want to close those chapters in their lives, too.

“Those are the most serious crimes. These homicides are so frustrating and there’s no good reason, and somebody needs to be brought to justice,” Zinke said.